I live close to an AM transmitter broadcasting in the kW of power. My RTL SDR dongle gets very overloaded. Using 2 AM broadcast filters, I have mostly managed to stop the overloading, at least from the main frequency.
However, generally on all bands, especially on HF, there is just a lot of noise. I assume this large amount of noise is due to the nearby AM transmitter.
My question is: given that I use a random long wire antenna going into my 9:1 "balun", is there a way to reduce noise? Would a good ground rod help?
I'm quite new to antenna design, and I'm unsure that when I do different random things (e.g. increase/decrese length or move it) to my long wire, when the noise reduces, I'm not sure if I've just attenuated my overall signal, or somehow managed to reduce the noise.
I don't understand if there is a distinction between noise and wanted signals when it comes to antenna design/placement.